The research proposed in this application aims at establishing the foundation for a systematic and simultaneous approach to the mechanisms of hallucinations and REM sleep. In cats, lesioning a discrete area in the pons, adjacent to the locus coeruleus, results in the disappearance of muscle atonia during REM sleep, with the animal exhibiting hallucinatory behavior. We intend to extend these studies to a species--the dog--which has a wider and richer repetoire of behavior. In addition, we will do more extended observations of innate and acquired behavior, before and after the lesions, in normal dogs and in dogs affected with narcolepsy; the latter are expected to have an enhanced propensity to hallucinate after the brainstem lesions since hypnagogic hallucinations are a major component of the illness.